A primary customer identity is usually a unique human being but can be a machine, or sometimes a company entity such as a department. On a telecommunications network itself, identity is represented by one or more identifiers recognised by elements of, or attached to, the network. In the context of mobile telecommunications, such identifiers are commonly the customers IMSI (International Mobile Subscriber Identity) that resides on a SIM (Subscriber Identity Module), a telephone number MSISDN (Mobile Subscriber Integrated Services Digital Network Number), or other important identities such as MAC (Media Access Control) address, IP address, email address and IMEI (International Mobile Equipment Identity).
In the GSM (Global System for Mobile communication) authentication is performed using a SIM inserted into the mobile communications device. This manages the connection to the network as well as the user identity and the network subscriber keys. There are two types of network service—home service and roaming service.
‘Roaming’ refers to extending the connectivity of a service to a location that is different from a home location. When a mobile communications device, such as a mobile telephone, travels with a user outside of their home operator coverage area—‘territory’—the device can still access services using roaming mechanisms/services. However, there are a growing number of people who live in more than one home and, of course, machines such as airplanes and cars don't have a ‘home’ in the human sense of the word. Such users are poorly served by current systems.
Another problem travelers experience as they travel near country or region borders is that mobile phones may inadvertently attach to a foreign network, even though they may be physically in a home territory. Under normal operation, once a handset (i.e. a mobile phone) is attached to a network, it remains attached to it until signal is lost or if the subscriber manually disconnects. As a result, the user is charged high roaming charges for an extended period even if though they were physically in their home territory. In some regions such as Canada, USA and India where there is national roaming this effect can lead to accidentally high bills even when the customer is not travelling at all.
There are few options available to users when travelling which help reduce these surcharges:—
One option for a user is to purchase a plurality of additional pre-pay subscriber identification modules (SIMs), one for each territory which the user visits. A SIM is a plastic card with embedded electronic circuitry, which has a unique serial number and an international number for the mobile user (IMSI). The SIM enables communication between the mobile device and available cellular networks. Therefore, by purchasing a plurality of different SIMs, —one for each territory—the user is able to replace the original SIM with an appropriate SIM for the territory being visited. In this way, the mobile device appears to be a subscriber of the foreign network, which means the user can make and receive calls or use data services without incurring roaming surcharges.
This option has many disadvantages:                the user must purchase and carry around a plurality of different SIM cards;        the user must ensure that there is sufficient credit in the accounts linked with each SIM card. Furthermore, it is not desirable to have unused credit on a number of different networks, as this credit may be wasted without being redeemed;        The act of maintaining a plurality of different SIM accounts is cumbersome and time consuming, involving considerable user interaction;        When the Subscriber swaps SIM their mobile number changes this means they are no longer reachable on their normally used number. Further if they make an outbound call their Caller Line Identifier (CLI) will be a new one and therefore unknown to the receiver. This may result in the called party refusing to answer that call as they do not recognise the caller.        Law enforcement agencies are frustrated in their endeavours to keep track of undesirable people as they effectively have to keep track of multiple copies of the same person.        
There are attempts in the prior art to address at least some of these problems.
WO2006/002951 (Brunnekreef) relates to an approach in which the user (or an application) on the mobile phone can pre-pend a (sometimes hidden) telephone number of an intermediate service that will accept the user's call, remove the pre-pended information and call the desired destination number. The caller then drops the call automatically and awaits a call-back. The intermediate service calls the user back to complete the connection, and this may give the user better calling rates than normal roaming surcharges. This has the disadvantage of introducing a delay in the communication channel while the user is trying to contact another party. Furthermore, the user gets a very poor user experience due to handset software compatibility issues: depending on the model of the mobile phone, the phone may appear to ‘do nothing’ until it gets the call back, strange messages such as ‘call failed’ or ‘call blocked’ may appear or the service may not work at all.
Another prior art approach is to have a mechanical device that includes a flexible strip (often called a slim SIM). This device physically connects multiple SIMs to a handset, and can be used with a means of switching between the SIMs. This device requires there to be some spare space within the handset to store the additional SIMs, and this solution is problematic to implement if the SIMs are not compatible with each other (e.g. use different data speeds or voltages). Alternately the Images of all but one SIM can be cloned onto the SlimSIM chip and a remaining SIM used—a one plus many clones solution. Again the physical form factor is incompatible with many handsets and the cloning of SIMs is unlawful in many countries and breaks contracts in almost all cases.
Multi-IMSI SIMs are available that offer the capability of being pre-programmed with a plurality of mobile subscriber data sets. The data sets are sometimes incorrectly referred to as IMSIs, hence the name ‘multi-IMSI SIM’, but are actually data sets which each comprise an international mobile subscriber identity (IMSI) and other network-related data. These SIMS have processing capability and an algorithm to present the correct set of data to the phone based on the location of that phone. This allows the phone to present as a ‘local’ subscriber to the network in question.
Many fixed format Dual and Multiple IMSI SIM systems have been sold by companies such a as VeriSign, Gemalto and these are described in various patent applications such as Cammileri (WO2007102003), Stadelmann (WO9955107), Salomon (WO0221872), Bongers (WO0049820). In such systems, a piece of software runs in the SIM or on the handset or a separate electronic module and makes decisions as to which IMSI to use given the location and available networks. Such systems are sometimes called SmartSIMs, but in fact this is a misnomer as all SIMs are smart and contain a microprocessor and memory to run network selection and authentication programs.
Such systems are however typically relatively inflexible to changes in network availability over time and require informed decision making from users. This can result in failures of operation and poor network choices.
An improved system is disclosed in the applicant's earlier WO 2011/036484. This discloses a system in which a central service—an “IMSI Broker”—is adapted to provision the SIM of a mobile handset with new identities as required. While this approach addresses certain problems of the prior art, it does not in itself solve the problem of making reliable and effective choices of identity at the mobile handset.